1. Field of the Invention
The present invention generally relates to a power supply technology, and more particularly, to a power supply technology for reducing the depletion of the power supply equipment.
2. Description of Related Art
With the development of electronic information technology, many portable apparatus with the battery such as cell phone, laptop should meet the demand of converting a battery voltage into an operation voltage. As a basic voltage regulating circuits employed in ordinary power suppliers, more and more voltage regulator down circuit (VRD) modules are used in a variety of electronic products.
Typically in a computer, a VRD is often used as a power supplier for a CPU. However, a conventional VRD usually adopts a fixed frequency. Therefore, when it is introduced in the computer, regardless whether the CPU is working in the state of a light load or a heavy load, the frequency of the VRD module remains unchanged. The VRD module thus often depletes considerably and results in power wastage.
In the present era when the environmental protection is increasingly given importance, it is commonplace to effectively use the inadequate or limited power supply. At present, with the increasing strict requirement of power consumption of electronic products, many developed countries have made standards and regulations towards standby power consumption. Therefore, many new technologies are developed in order to meet the newly issued standards, which allow the switching power supply to work with a lower switching frequency when the electronic product works in a state of a light load or standby.
Taiwan patent No. TW00509832 discloses a power conversion unit which outputs a direct current (DC) controlled by a pulse signal via a pulse width modulator (PWM) unit. The power conversion unit further includes a calculation unit for detecting the current output, and determines a calculation mode of a load according to a value of the detected current output. When the current output is faded, a value smaller than usual value is read to a periodical recorder, the PWM generates the pulse signal according to the value recorded in the periodical recorder and the calculation unit.
Taiwan patent No. TW00509832 discloses that the calculation unit detects the current output, and thus determines the calculation mode of the load, and then adjusts the pulse signal. This provides a solution for the problem of CPU consuming too much power. However, it fails to provide a solution for the problem of the VRD module consuming too much power. Furthermore, the aforesaid device requires hardware such as calculation unit, micro controller unit (MCU) with high cost and a relatively complicated detection process.